Office friendships can be a boon -- or a bane

Strong ties to colleagues can cut both ways.

Research tells us that people are happier and more productive when they have good friends at work, but the fact is, most of us don't.

Fewer than one in three employees in the U.S. has a close friend at work, someone in whom they confide, according to a study by the University of Michigan. Americans also are less likely to extend professional ties outside work than counterparts in other cultures, even though they feel energized when they do, the study found.

"If socializing with co-workers is energizing, why don't we do it more often?" asks co-author Aleksandra Kacperczyk, a doctoral student at the university's Ross School of Business, who, by the way, did not socialize with either of her co-authors.

The researchers conclude that America's work ethic -- work and pleasure don't mix -- may explain the cultural differences.

At least this much is certain: Office friendships can get complicated.

"The reason it's so complicated is you need positive, strong connections at work to want to go there," says author and friendship expert Jan Yager. "Friendship is based on openness and trust and self-disclosure, and in the workplace this can backfire."

Natalie Nussbaum, 29, a financial consultant at a large health insurer, so far is blissfully untouched by such consequences. Most of her friends are people she works with or worked with at her previous job. She confides in them, plays sports and parties with them, even vacations with them.

When she and a colleague vacationed in Miami, the pair stayed with, you guessed it, a friend from work who had transferred there.

Did they talk about work? "Almost not at all," she says.

But she can see the possibility of betrayal and heartache. Two of her friends went from hanging out together several times a week to "not really talking at all" after they competed for a promotion.

The victor won the promotion but lost a friend.

Marketing executive Dan O'Brien lost two good friends when their work relationship soured. They had grown close while collaborating at a large ad agency in Chicago, so tight, in fact, that they attended one another's family celebrations.

The rift occurred when an important client put its account up for review. O'Brien, who managed the account, geared up to fight for it, but his friends, who worked on the creative team, felt it was a lost cause.

"I really lashed out at these guys," recalls O'Brien, 51, now president of interactive marketing agency Brand Clariti in Chicago. "It was traumatic. I was the leader, and it was going to be on my back that this account walked out the door after 50 years. I felt a lack of passion and commitment from them. I felt like they betrayed us. It was cold, it was icy."

A year later, after the client fired the agency, O'Brien apologized, but it was too late.

The experience hasn't stopped him from mixing work and friendship, but he's aware of the risks.